Phosphor and cathode-ray tube using the same

Abstract

Disclosed are terbium-activated oxide phosphors having incorporated, at least one of ytterbium, thulium, samarium and europium. Incorporation of the element (s) has made it possible to produce phosphors exhibiting high brightness and suffering little brightness deterioration under high-density electron bombardment.

What is claimed is: 
     
       1. A green-emitting phosphor having a composition of:   (Y.sub.1-x-y-z Gd.sub.z Tb.sub.x Yb.sub.y).sub.2 SiO.sub.5     in which 0.05≦x≦0.15, 1×10 -6  ≦y≦2×10 -2  and 0≦z≦0.45, wherein the green-emitting phosphor emits colors in the range of 0.325≦X≦0.36 and 0.54≦Y≦0.65 in emission chromaticity coordinates.   
     
     
       2. A green-emitting phosphor having a composition of:   (Y.sub.1-x-y-z Gd.sub.z Tb.sub.x M.sub.y).sub.2 SiO.sub.5     in which 0.05≦x≦0.15, 1×10 -6  ≦y≦1×10 -3 , 0≦z≦0.45, and M is at least one element selected from the group consisting of thulium and samarium, wherein the green-emitting phosphor emits colors in the range of 0.325≦X≦0.36 and 0.54≦Y≦0.625 in emission chromaticity coordinates.   
     
     
       3. A cathode-ray tube comprising: a faceplate;   a phosphor film formed on a surface of the faceplate which emits colors in the range of 0.325≦X≦0.36 and 0.54≦Y≦0.625 in emission chromaticity coordinates, the phosphor having a composition of   (Y.sub.1-x-y-z Gd.sub.z Tb.sub.x Yb.sub.y).sub.2 SiO.sub.5     in which 0.05≦x≦0.15, 1×10 -6  ≦y≦2×10 -2  and 0≦z≦0.45;     an aluminum deposition film formed on the oxide phosphor film;   an electron gun to irradiate the oxide phosphor film with electron beams; and   means of allowing the electron beams to scan on the faceplate.   
     
     
       4. A cathode-ray tube comprising: a faceplate;   a phosphor film formed on a surface of the faceplate which emits colors in the range of 0.325≦X≦0.36 and 0.54≦Y≦0.625 in emission chromaticity coordinates, the phosphor having a composition of   (Y.sub.1-x-y-z Gd.sub.z Tb.sub.x M.sub.y).sub.2 SiO.sub.5     in which 0.05≦x≦0.15, 1×10 -6  ≦y≦1×10 -3 , 0≦z≦0.45, and M is at least one element selected from the group consisting of thulium and samarium;     an aluminum deposition film formed on the oxide phosphor film;   an electron gun to irradiate the oxide phosphor film with electron beams; and   means of allowing the electron beams to scan on the faceplate.